Machine for sharpening endless metal band blades



Jime 15, I954 G. HILL ETAL 2,680,940

MACHINE FOR SHARPENING ENDLESS METAL BAND BLADES Filed Feb. 27, 1952 5 Sheets-$heet l INVENTORS GORDON HILL LOUIS L. JENSEN mwmzk ATTORNEYS June .15, 1954 a. mu. ETAL 2,680,940 MACHINE FOR SHARPENING ENDLESS METALVBAND BLADES Filed Feb. 27, 1952 5 Sheets-Sheet 2 1 mm" E ihu v INVENTORS GORDON HILL LOUIS L. JENSEN ZWMVQIQ ATTORNEYS June 15, 1954 Filed Feb. 27, 1952 G. HILL gnu, 2,680,940

MACHINE FOR SHARPENING ENDLESS METAL BAND BLADES 5 Sheets-Sheet 3 INVENTORS GORDON HILL LOUIS L- JENSEN W ATTORNEYS J1me 1954 65. HILL ETAL 2,680,940

WINE FOR SHARPENING ENDLESS METAL BAND BLADES Filed Feb. 27, 1952 5 Sheets-Sheet 4 INVENTORS GORDON m LOUIS L. JENSEN ATTORNEYS;

I I I L June T5, 1954 5. HILL ETAL 2,680,940

MACHINE FOR SHARPENING ENDLESS METAL BAND BLADES Filed Feb. 27, 1952 5 Sheets-Sheet. 5

LOUIS L. JENSEN ATTORN EY UNITED STATES FATENT OFFICE MACHINE FOR SHARPENING ENDLESS METAL BAND BLADES Gordon Hill, Bettendorf, and Louis L. Jensen, Davenport, Iowa, assignors to The Bettendorf Company, Maryland Bettendorf, Iowa, a corporation of Application February 27, 1952, Serial No. 273,626

10 Claims.

The present invention is a machine for sharpening endless metal band blades in which one or more grinding wheels engage a continuously moving flexible metal band along one edge thereof Figure 1 is a top plan view of a machine embodying the invention;

Fig. 2 is a fragmentary vertical section taken on the line indicated at 2-4 in Fig. 1, showing to sharpen said edge, the machine being partic- 5 the mechanism for simultaneously adjusting the ularl applicable to the sharpening of the scaltwo hacking pulleys with respect to the two grindlopc-d edges of endless slicer blades such as used ing wheels; in bread slicing machines. Fig. 3 is a horizontal section through one of In the machine embodying the invention herethe grinding wheels, showing the grinding wheel in shown the endless band blade to be sharpened 1 in engagement with a portion of the endless metal is supported upon horizontally disposed pulleys, band on one of the supporting pulleys; one of which is actuated by suitable means such 4 is a fragmentary vertical section upon as a counterweight to maintain a predetermined an enlarged scale showing a grinding wheel in tension on the band, and one of which is driven engagement with aband blade; to move the band at a uniform speed past two 5 Fig. 5 is a side elevation of the machine; grinding wheels, one mounted interiorly of the Fig. 6 is a fragmentary vertical section through endless band and the other exteriorly thereof. the band driving pulley taken on the line indi- The grinding wheels have band engaging faces cated at 6-5 in Fig.5; that are inclined at a small angle to the vertical i 7 is a h i t section t k on t i and that engage the inner and outer sides of the indicated t 7 'g 1 n a the 11010 e ereof t Sharp Said Fig. 8 is a vertical section taken on the line intop edge. Opposite each grinding wheel there is (ligated t g g in Fig 5; a b n p r n d backing p ll y which has Fig. 9 is a top plan View on an enlarged scale a cylindrical face engag g e Sid-c 0f e band showing the two grindin wheels with their drivopposite hat engaged by h opp d ri d n mg motors and the backing pulleys for support- Wheel and a p riph ral 511011113161 engaging the ing the portions of the band acted upon by the bottom of the band to hold the 1 0113 f the grinding Wheels; d engaged by the grinding Wheel against Fig. 10 is a transverse vertical section through ticfil movement the grinding wheel supports taken on the broken The grinding wheels and backing pulleys are linemdicated at 53 |g;. 1 9; relatively adjustable to provide the desired depth Fig 11 is a fragmentary front elevation of t of o t and y be 50 adjusted that the bandWin manually operable lever for rocking the grindbe sharpened in 0116 pass- Means is provlded ing wheel supports to effect a lateral adjustment for quickly relieving the tension on the band of the grinding wheels with respect to the band and for separating the grinding wheels and posupporting pulleys; Sitifming 1311118575 80 that sharpened band can Fig. 12 shows the mechanism for rocking one be quickly and easily removed from the pulleys of the grinding wheelsupports;

a d to be sharpened can be quickly Fig. 13 is a vertical section taken on the line mounted ther o indicated at l3--l3 in Fig. 9; and

O j e invention are 130 prOVide a 40 Fig. 14 is a vertical section taken on the line simple, rapidly operating band sharpening mechindicated at g gs in Fig 9 anism, to provide simple and convenient means The machine of t present invention is r p p y p ti i h grinding Wheels w vided with a Supporting frame 1 which has front respect to the b d to e p d, provide and rear table portions 2 and 3 above which are supporting pulleys for the band which firmly supmounted a front driving pulley and a rear tenport portions of the band acted upon by the sioning pulley 5. The pulleys t and 5 are horirin ins W l n p per p i n with respect to zontally disposed and are mounted in vertical the grinding wheels, and to provide a machine shafts 6 and E. The pulleys 4 and 5 serve to supupon which the band to be sharpened can be port an endless flexible metal band B which is to quickly and easily mounted and from which a be sharpened. Two grinding wheels 3 and 9 are sharpening hand can be quickly and easily reprovided, the grinding wheel 8 being mounted d interiorly of the band B for engagement with Reference should be had to the accompanying the inner face of the band and the grinding wheel drawings forming a part of this specification in 9 being mounted exteriorly of the band for enwhich: do gagement with the outer 'face thereof. The

3 grinding wheels 3 and 9 are driven at the desired grinding spec .s by suitable means such as electric motors it? ii, to the shafts of which the grinding wheels 3 and 9 are attached.

For positioning the portions of the band B which are engaged by the grinding wheels during movement of the band, positioning pulleys l2 and :3 are provided. The pulley l2 engages the exterior face of the band .B and supports the portion of the band engaging with the grinding wheel 8. The pulley 13 engages the interior face of the band and supports the portion of the band with which the grinding wheel 53 engages. pulleys i; and i3 are mounted on vertical shafts l4 and it which are preferably tubular and which serve to support and deliver lubricant to nozzles l5 and i? attached. thereto and positioned over the portions of the band with which the grinding wheels engage. The motors l6 and H with their grinding wheels 8 and 9 are adjustable toward and away from the band positioning pulleys I2 and i3 to adjust the depth of the cut by suitable means such as screws l8 and Hi. In order to maintain the endless band B at the proper elevation during its travel, the pulleys 4, 5, l2 and I3 are each provided with a peripheral shoulder against which the bottom edge of the band B engages.

The two grinding wheels 8 and 9 may be of identical construction, each being provided with a fiat band engaging face 2! that perpendicular to the axis of rotation of the wheel. As shown in Fig. 3, the annular flat face 2! of each grinding wheel is disposed between the periphery of the wheel and a central recess 22. Each grinding wheel is preferably enclosed within a housing 23 which is closed except for a Window 24 opening to the face 2i and of a size to receive a small arc of the band positioning pulley. The axis of each grinding wheel is displaced laterally with respect to the axis of the positioning pulley with which it cooperates a distance slightly less than the radius of the grinding Wheel so that the face 2| of the grinding wheel is properly positioned for engagement with a portion of the band B on the positioning pulley substantially at the center of the arc of contact of the band with the pulley. The planes of the grinding faces 2! of the wheels 8 and 9 are oppositely inclined and at small angles to the vertical to provide the desired taper on the sharpened edge of the band B.

The supporting shaft '1 of the tensioning pulley 5 is carried by a slide 25 that is mounted in a longitudinal way 26 beneath the table 3. A cable 2'! attached to the slide 25 passes over a pulley 28 at the rear end of the frame I and has a weight 29 attached thereto which exerts a constant pull on the slide 25 to maintain a constant tension on the band B. Manually controlled means is pref erably provided for moving the slide 25 forwardly in opposition to the weight 29 to relieve the tension on the band B when it is desired to remove a band from the machine and to position the pulley 5 for reception of a band to be sharpened.

As herein shown, the slide actuating means is a fluid pressure cylinder 38 operably connected to the slide 25 and provided with a manually operable control valve 3! by means of which fluid under pressure may be admitted to the cylinder 38 to retract the slide 25.

The pulleys l2 and !3 are mounted for adjust ment toward and away from the band B to increase or decrease the arcuate engagement of the band with the pulleys and to separate the pulleys from the grinding wheels to facilitate rethe pulleys i2 and I3 toward or away The i moval of a sharpened band or insertion of a band to be sharpened.

As shown in Fig. 14, the pulley supporting shafts i i and 15 are mounted in a supporting member 32 at equal distances from and on opposite sides of a vertical pivot 33 connecting the supporting member 32 to the frame l. Angular adjustment of the supporting member 32 to move from the grinding wheels 8 and 9 is effected by means of a manually operable lever 3% that is attached to the upper end of a vertical shaft 35 journaled in the frame i and having a cam 35 keyed thereto which engages with a horizontal pin 31 that slides in a guide 38 and that is interposed between the cam 36 and one end of the supporting member 32. The tension applied to the band B exerts a thrust on the supporting member 32- in a direction to press the pin 31 against the periphery of the cam 35. Adjustment of the lever 35 in one direction shifts the pulleys l2 and it toward the band B to engage the portions of the band on the pulleys with the grinding wheels 8 and 9. Movement of the lever 3Q in the opposite direction permits the support 32 to be moved in a di rection to move the pulleys l2 and 13 away from the grinding wheels 8 and 9.

The vertical shaft 6 carrying the pulley t is driven by an electric motor 39 through a belt 60, a reduction gearing in housing M and a reduc tion gearing in housing Ma, the reduction gearings being connected through a sprocket chain 32. In order to enable the band B to be adjusted manually when the shaft E is stationary, the band driving pulley iiis connected to the'shaft 5 through an overrunning clutch which is shown in Figs. 6 and '1. As shown in Fig. 6, the pulley 5 has a hub 53 which is rotatably mounted on a collar 4t that is keyed to the shaft 6. The collar 44 has a radially extending arm 45 which supports a cam 45 that provides a driving engagement in one direction between the shaft 6 and the pulley l. vThe cam 45 is mounted on a vertical pivot A? and has a cam face 48 that is eccentric with respect to the pivot 41. Upon rotation of the shaft 5 in the direction in which it is driven by the motor, the cam 45 is tightened between its pivot l! and the periphery of the hub 43, clamping the hub to the collar M for rotation therewith. When the pulley t is turned in the direction opposite that in which it is driven by the motor 39, the cam is rolled out of clamping engagement, permitting the wheel l to turn freely. With the motor 39 stopped the operator can turn any of the pulleys in a direction to drive the pulley 4 in a reverse direction and thereby adjust the band B to bring any desired portion thereof into position to be acted upon by the grinding wheels. In order to insure clutching engagement of the cam 46 with the hub 63 when the shaft 6 is driven, a spring 49 urges the cam 45 toward its clamping position.

An oil reservoir or sump 50 is provided beneath the pulleys l2 and i3 and grinding wheels 8 and 9, in position to receive lubricant draining from the pulleys and grinding wheels, and a pump 5! is provided which delivers lubricant from the reservoir 50 through pipes 52 and 53 to the tubular shafts l4 and i5 and nozzles 15 and H. In order to permit free movement of the supporting member 32, the upper end portions of the pipes 52 and 53 may be connected to the tubular shafts M and I5 by flexible rubber tubes 52a and 53a, as shown in Fig. 14.

The screws I8 and I9 are identical and each has an enlarged cylindrical inner end 54 that has a sliding and rotating fit in a sleeve 55 that is pivotally supported by transverse horizontal trunnions 56. The screws I8 and I9 are disposed at a slight inclination to the horizontal, the outer ends thereof being slightly higher than their inner ends and mounted in nuts 57 that are secured to brackets 58 attached to the frame I. Each of the nuts 53 is adjustable vertically on the bracket to vary the inclination of the screw, the nuts 5? being secured to the brackets 5% by means of bolts 59 which pass through vertical slots in the brackets 58. The screws I 8 and I9 are oppositely inclined and each is disposed parallel to the axis of the grinding wheel supported thereon. The inclination of the screws to the horizontal determines the taper of the sharpened edges of the band, the usual adjustment being about 7 so that the band engaging faces 25 of the grinding wheels are disposed at substantially 7 to the vertical.

The motors ill and I I are mounted upon identical brackets 6i that are pivotally mounted on unthreaded portions 52 of the screws I8 and it, the brackets 58 being mounted between the enlarged inner ends as of the screws and collars 53 carried by the screws I8 and I9 and engaging the outer ends of the brackets 5!. Each of the screws I8 and Ill has a knob 64 attached to its outer end and each of the knobs 64 is graduated circumferentially so that a pointer 65 attached to the nut 57 will indicate the extent of angular adjustment of the screws to thereby accurately indicate the amount of movement imparted to the grinding wheels 8 and 9 upon each adjustment thereof.

The brackets 65 may be rocked upon the screws I3 and it to shift the grinding wheels 3 and 9 laterally to shift the point of engagement between the grinding face 2i of each of the grinding wheels and the band B. The brackets 6! supporting the grinding wheels 8 and 9 are provided with laterally extending arms 66 and 6'! which are connected to eccentrics $3 and 69 on a horizontal shaft iii carried by the frame substantially midway between the screws I8 and It. By turning the shaft it the supporting brackets BI can be simultaneously rocked in opposite directions to shift the grinding wheels 8 and 9 laterally with respect to the band positioning pulleys. For adjusting the shaft "it a hand crank H is provided at the outer end of the shaft, the crank ll being secured in different positions of angular adjustment by means of a spring pressed pin 72 that engages in angularly spaced openings 73 in a plate M attached to the frame I. Lateral adjustments of the grinding wheel serve to equalize the wear on the faces 2i so that less frequent dressing is required.

As shown in Fig. 14, the band positioning pul leys I 2 and I 3 which are of identical construction, are each provided with an elongated downwardly extending hub portion '15 provided at the ends thereof with roller thrust bearings 75 and I? which serve to position the pulleys vertically on the shafts I 4 and i5 and which permit free rotation thereof. The inner race of the lower bearing 77 is supported on a collar 18 attached to the shaft, and the inner race of the top bearing '56 is engaged by a cap I9 which is held in place by nuts 80 on the upper ends of the shafts I6 and I5. The nozzles I6 and I? are attached to nipples 3! screwed intot the upper ends of the shafts I 4 and i5 and the flexible ends 52a and 53a of the pipes 52 and 53 are connected to the lower ends of the tubular shafts I4 and I5 by nipples 82.

The electric motors I0 and I I driving the grinding wheels 8 and 9 are provided with controlling switches 83 and 8d. The motor 39 driving the band B is controlled by a switch 85 and the pump 5! is controlled by a switch 86.

After each grinding operation the driving motor 38 is stopped and the pulleys I2 and 53 are retracted from the grinding wheels 8 and 9 by turning the cam 36 by means of the lever 34 in a direction to permit the pin 3'! to move toward the shaft 35. After the grinding wheels are disengaged the valve 3I is operated to admit pressure to the cylinder 36 and retract the pulley 5, thereby relieving the tension on the band so that it can be readily lifted from the pulleys. With the pulleys so. positioned a band to be sharpened can readily be placed on the pulleys, after which the pressure in the cylinder 30 is released by actuating the valve 3! so that the band is subjected to tension applied by the weight 29 attached to the pulley 5. The motor 39 is then started to drive the band and also the grinding wheel motors IE3 and Ii. The grinding wheels are then simultaneously shifted to their band engaging positions by turning the cam 36 by means of the lever 3 in a direction to press the pin 37 toward the pivoted supporting member 32.

' During operation the grinding wheels can be simultaneously adjusted by means of the crank II to shift them tangentially of the pulleys I2 and It so as to engage different portions of the grinding wheels with the band blade. Each grinding wheel may be adjusted to vary the inclination of its band blade engaging face by loosening the bolts 59 and adjusting the nut 51 vertically in the bracket 58.

If it is desired to grind or regrind certain portions only of the blade, the blade can be adjusted with respect to the wheels by stopping the motor 3i! and turning any of the pulleys by hand in a direction opposite that in which they are driven by the motor 39, the overrunning clutch- 46 through which the pulley 4 is driven by the motor 39 permitting such movement.

It is to be understood that in accordance with the provisions of the patent statutes, variations and modifications of the specific devices herein shown and described may be made without departing from the spirit of the invention.

What we claim is:

l. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tensioning and driving said band, said support including a positioning and backing member engaging the in terior face of the band throughout the major portion of its width and a positioning and backmember engaging the exterior face of the band throughout the major portion of its width, each of said members having positioning shoulders for engagement with one of the band edges,

two grinding wheels, one mounted exteriorly of the band for engagement with the portion of the band passing the interior backing member and with the face thereof opposite that engaged by the interior backing member and the other mounted interiorly of the band for engagement with the portion of the band passing the exterior backing member and with the face thereof opposite that engaged by the exterior backing member, said grinding wheels having faces that engage with the faces of the band along the edge thereof opposite that engaged by said shoulders and that are oppositely inclined with respect to the band faces, means for driving said grinding wheels, and means relatively adjusting the grind ing wheeis and backing members to engage the grinding wheels with the band or to disengage the same.

2. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tensioning and driving said band, said support including a positioning and backing member engaging the interior face of the band throughout the major portion of its width and a positioning and backing member engaging the exterior face of the band throughout the major portion of its width, each of said members having positioning shoulders for engagement with one of the band edges, two grinding wheels, one mounted exteriorly of the band for engagement with the portion of the band passing the interior backing member and with the face thereof opposite that engaged by the interior backing member and the other mounted interiorly of the band for engagement with the portion of the band passing the exterior backing member and with the face thereof opposite that engaged by the exterior backing member, said grinding wheels having faces that engage with the faces of the band along the edge thereof opposite that engaged by said shoulders and that are oppositely inclined with respect to the band faces, means for driving said grinding wheels, means for adjusting each grinding wheel to vary its inclination with respect to the band blade face with which it engages, and means for simultaneously relatively adjusting said grinding wheels and backing members to engage the grinding wheels with the band or to disengage the same.

3. A machine for sharpening endless metal band blades comprising a supporting frame, a slide mounted for horizontal movement on said frame, a pair of horizontally disposed band receiving pulleys carried by said frame, one of said pulleys being mounted on said slide, means exerting a thrust on said slide in a direction to maintain tension on said belt, manually controlled means for moving said slide in opposition to said thrust to release the tension on said belt, means for driving one of said and supporting pulleys, each having a peripheral band supporting shoulder for engaging the bottom edge of said band, one backing pulley engaging the interior face of the band and the other backing pulley engaging the outer face of the band, two grinding wheels each mounted adjacent a backing pulley for engagement with a portion of the band that engages a backing pulley, each grinding wheel having a blade engaging face inclined at a small angle to the vertical that engages the band along the edge there of opposite that in engagement with said shoulders and on the face opposite that engaged by the adjacent backing pulley, means for driving said grinding wheels, and means for relatively adjusting said backing pulleys and grinding wheels to engage the grinding wheels with the band or to disengage the same.

4. A machine for sharpening endless metal band blades comprising a support, spaced horizontal band receiving pulleys carried by said support, means for driving one of said pulleys, a supporting member mounted on said support to swing horizontally about a vertical axis intermediate its ends, horizontally disposed band posipulleys, two band backing tioning pulleys journaled upon said member on opposite sides of said axis and engageable one with the outer face of the band and the other with the inner face of the band, means for adjusting said member angularly, and two grinding wheels mounted on said support independently of said support member one adjacent each of said positioning pulleys for engagement with the face of the band opposite that engaging the adjacent pulley, means for driving said grinding wheels, and means for independently adjusting said grinding wheels.

5. A machine for sharpening endless metal band blades comprising a support, spaced horizontal band receiving pulleys carried by said sup port, means for driving one of said pulleys, a supporting member mounted on said support to swing horizontally about a vertical axis intermediate its ends, horizontally disposed band positioning pulleys journaled upon said member on opposite sides of said axis and. engageable one with the outer face of the band andthe other with the inner face of the band, each of said pulleys having a peripheral shoulder for engagement with the bottom edge of the band and a cylindrical face for engagement with a side face of the band, means for adjusting said supporting member angularly to increase or decrease the arcuate engagement of said positioning pulleys with said band, a grinding wheel positioned opposite each of said positioning pulleys, each grinding wheel having a flat band engaging face lying in a plane inclined at a small angle to the vertical and engageable with the top edge portion of the band passing over the oppositely positioned pulley, means for driving said grinding wheels, means for adjusting said grinding wheels toward 01' away from said band, and means for tilting said grinding wheels to vary the inclination of their band engaging faces.

6. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tightening and driving an endless band blade, a positioning pulley having a peripheral shoulder for engagement with an edge of the band blade and a cylindrical peripheral face for arcuate engagement with a side face of said band blade, a grinding unit mounted adjacent the portion of said peripheral face engaging said band and radially outwardly thereof, said unit comprising a supporting member mounted for linear movement toward and away from the axis of said pulley and toward and away from the face of the band opposite that engaging the pulley, a shaft mounted on said supporting member and extending in the direction of movement thereof, means for driving said shaft and a grinding wheel attached to said shaft and having a face perpendicular to said shaft engageable with the portion of the band engaging the pulley and along the edge thereof opposite that engaged by said shoulder, means for adjusting said supporting member toward and away from said pulley, and means for adjusting said supporting member about an axis transverse to said shaft to vary the inclination of said band engaging face.

'7. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tightening and driving an endless band blade, a positioning pulley having a peripheral shoulder for engagement with an edge of the band blade and a cylindrical peripheral face for arcuate engagement with a side face of said band blade, a grinding wheel mounted adjacent the portion of said peripheral face engaging said band and radially outwardly thereof for movement toward and away from the portion of the band in engagement with said pulley, said grinding wheel having a fiat band engaging face perpendicular to the axis of rotation of the wheel engageable with the face of the band opposite that engaging the pulley along the edge thereof opposite that engaged by said shoulder, means for driving said grinding wheel, means for adjusting said wheel bodily toward or away from said peripheral face of said pulley, and means for adjusting said wheel angularly about an axis transverse to its axis of rotation to vary the inclination of said band engaging face.

8. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tightening and driving an endless band blade, a positioning pulley having a peripheral shoulder for engagement with an edge of the band blade and a cylindrical peripheral face for arcuate engagement with a side face of said band blade, a grinding Wheel mounted adjacent the portion of said peripheral face engaging said band and radially outwardly thereof for movement toward and away from the portion of the band in engag e ment with said pulley, said grinding wheel having a fiat band engaging face perpendicular to the axis of rotation of the wheel engageablewith the face of the band opposite that engaging the pulley along the edge thereof opposite that engaged by said shoulder, means for driving said grinding wheel, means for adjusting said wheel bodily toward or away from said peripheral face of said pulley, means for adjusting said wheel angularly about an axis transverse to its axis of rotation to vary the inclination of said band engaging face, and means for adjusting said grinding wheel laterally to bring different portions of said band engaging face to band engaging position.

9. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tensioning and driving said band, a supporting member mounted to turn about a vertical axis intermediate its ends, hollow vertical shafts mounted in said supporting members on opposite sides of said vertical axis, a band positioning pulley on each of said shafts, each of said pulleys having a peripheral shoulder 10 for engagement with the bottom edge of said band and a cylindrical peripheral face above said shoulder for arcuate engagement with said band, one of said pulleys engaging said band interiorly and the other exteriorly, a grinding wheel mounted for engagement with the upper edge portions of the band passing over each of said pulleys, means for driving said grinding wheels, a lubricant spout attached to the upper end of each of said shafts and overlying the band engaging portions of said pulleys, a lubricant reservoir, and means for pumping lubricant from said reservoir through said hollow shafts to said spouts.

10. A machine for sharpening endless metal band blades comprising a band blade support having means for supporting, tensioning and driving said band, a supporting member mounted to turn about a vertical axis intermediate its ends, hollow vertical shafts mounted in said supporting member on opposite sides of said vertical axis, a band positioning pulley on each of said shafts, each of said pulleys having a peripheral shoulder for engagement with the bottom edge of said band and a cylindrical peripheral face above said shoulder for arcuate engagement with said band, one of said pulleys engaging said band interiorly and the other exteriorly, a grinding wheel mounted for engagement with the upper edge portions of the band passing over each of said pulleys, means for driving said grinding wheels, means for adjusting said supporting member angularly to simultaneously adjust said pulleys, and means for simultaneously adjusting said grinding wheels.

References Cited in the file of this patent UNITED STATES PATENTS Lyon Feb. 13, 1951 

